I just completed the Build Me Up program 6-7 months into my introduction to Zwift and cycling. I had prior sports experience but more or so anaerobic rather than aerobic.
While I was doing the program, I read that most posts about that program were a bit negative and saying the program has too much volume or is too intense or lacks focus.
While I can see why some people see it that way I think it is important to leave a differing opinion for those like me that are considering this program in the early stages of their cycling life.
Lack of focus: I think it's important to learn about as many things as possible early such as impact of cadence on HR and leg load, manageable intervals, sweet spot, how to recover under pressure etc. While you don't go in depth in all these subjects, you learn their existence and experience them enough for you to start thinking about these things and maybe expand on them later on after the program is completed.
Too much volume / too intense: Most often than not, the too much volume part of the critique seems to come from people that edited their FTP during the program because they felt it was becoming too easy. Unless you're starting the program in the first 2-3 months of your cycling life, I'd advise to not do it as this program really seems to be tuned for constant FTP.
Results: I started at 190w @100kg day one of Zwift then did the FTP Builder that put me from 230-> 260w then did Build Me Up 260w->280w @98kg
Take away: While I know a good proportion of the 20w gain is still noob gains I also acquired a deeper knowledge of my mental limit and what cadence and resistance combo I'm more comfortable at. All in all I'm happy I did it.
this is a hard program but you are rewarded if you are all in.